We have been working to improve the outcome of systemic fungus infections. To accomplish this we have been studying: 1. The basis of the phase transition of the dimorphic fungus Histoplasma capsulatum. 2. Methods of improving therapy of systemic fungus infection by exploiting the membrane properties of amphotericin B to increase the effects of second agents against fungi; and by utilizing the immunoadjuvant properties of this class of drug to stimulate host resistance to fungal infections. 3. Methods of improving the diagnosis of systemic fungus infections based on the development of a radioimmunoassay for fungal antigen.